Rockfalls are generally defined as groups of loose rocks or rock formations that become dislodged from a rock face under the influence of gravity. Rockfalls present a significant hazard for personnel and equipment that may be present in the pathway of the rockfall. An active rockfall area can be extremely hazardous; a falling rock contains a tremendous amount of energy, and even relatively small rocks can cause significant damage to equipment and structures, and can cause loss of life.
There are a number of mitigation techniques available to reduce the potential damage from rockfall. During construction practices, it is often necessary to provide temporary protection from rockfalls. One type of commonly used temporary barrier includes the use of a flexible barrier such as metal fencing or mesh that is secured by anchors to the slope at designated locations that is subject to rockfall events. If a rockfall occurs, the rock and associated debris are routed under the flexible barrier and between the mesh and the rockfall face. This channeling effect controls the fall of rocks and debris to prevent the rocks from free falling and causing potentially devastating damage to equipment and potential loss of life
An additional measure for mitigation is to excavate a catch basin at the base of the slope so any falling rocks are caught within the basin and therefore cannot fall below the location of the basin.
There are a number of US and foreign patent references that disclose barrier systems to mitigate damage from rockfalls. Some of these references provide complex flexible barrier configurations while others employ a large number of anchors or posts for supporting one or more flexible barrier members. One common theme however in most if not all of these references is that they are complex and require significant resources and manpower to install.
While there may be a number of solutions available for limiting the hazards associated with rockfalls and landslides, there are some inherent drawbacks with many of these solutions. For rockfall barriers that incorporate anchors such as metal posts to secure the metal barrier fencing, it can be very difficult to install the requisite number of posts on difficult to access sloping surfaces where rockfalls are actively occurring. Furthermore, the posts are commonly designed to break away or bend if the posts receive a direct hit from a falling rock or if the mesh experiences an excessive impact from falling rocks and debris. As a result of a direct hit or the force of many rocks striking the barrier fencing adjacent a post, the post must be replaced in many circumstances which require additional resources and manpower to repair or reset the system. For larger more catastrophic rockfalls, a number of adjacent posts may be destroyed which can further compromise the overall integrity of the barrier system, and may allow the escape of falling rocks and debris.
Therefore, there is a need to provide a rockfall barrier system that is capable of withstanding direct hits from rocks and falling debris without having to individually replace each post or anchor system that is used to hold the fencing. There is also a need to provide a rockfall barrier system that is easy to install, repair, and to minimize the length of exposure time of personnel to rockfall hazards. There is also a need to provide a rockfall barrier system that can effectively achieve dissipation of the energy associated with a rockfall in a cost-effective manner yet ensuring the safety of personnel and equipment that may be located in the rockslide area.